Ever since I’d arrived in Panama, I’d been hearing about San Blas, an archipelago of more than 350 islands in the Caribbean Sea. The suggestions to visit came both from Panama locals and a friend back home in New York, who claimed a day spent boating around San Blas was by far the most exciting adventure she had during her travels.

“It’s not like going to a resort or something," she explained. “It’s more of a Robinson Crusoe experience: just you and the islands.”

Curiosity piqued, I booked the winding two-hour drive from Panama City to Golfo de San Blas, the coastal city where I’d catch my boat, and started doing some research. And while my friend was right to warn me not to expect any luxuries, it quickly became evident that it wouldn’t exactly be just “me and the islands”. Instead, I would be a guest of the Guna people, an indigenous group that has called the islands home for hundreds of years.

San Blas, known as Guna Yala to its natives, is autonomously controlled by the Guna. The indigenous tribe staged a revolution against the Panamanian government in 1925 and was granted sovereignty over the land, which allows them to operate under their own constitution and government. The Guna inhabit less than 100 of the islands, but fiercely protect them all, strictly monitoring tourism (you need to bring your passport, even for just a day trip) and land use. This means large-scale developments are non-existent, as are many modern staples.

When I finally set eyes upon the islands, I instantly understood why they have long captivated tourists and locals alike. Appearing out of the horizon like a mirage, each island seemed to have been crafted perfectly upon the crystal-clear, turquoise water, with palm-tree dotted beaches and pale-yellow sand. There were no buildings, save for small, basic huts made of natural materials, allowing a completely uninterrupted view from island to island. The dozen or so of us travellers on the boat fell silent, reaching for our cameras to capture the moment.

The first island we docked at was identified only by a small wooden sign: Aroma Island. Our Guna guide, Eulog’io, spoke very little English, leading us around instead with frequent gestures and an easy smile. He handed out snorkels, bottles of water, and, for those interested, shots of rum to pour into freshly picked coconuts, a concoction the Gunas called “coco loco”.

Aroma Island is one of the few that allows travellers to spend the night, but it does not offer any hotel facilities. Instead, guests can bring their own camping gear or stay in the same type of small huts the locals live in, most without electricity and all without built-in plumbing. Tourists are welcome to join in the Guna way of life, meaning a night here will likely include meeting and eating alongside of your guide’s family.

Our next destination was Dog Island, where we stopped for lunch. There was no menu as each day’s meal depends on that morning’s haul. That day was a good one: heaping plates of steaming grilled fish, paired with coconut rice and watermelon. Without the distractions of mobile phones and wi-fi, conversation flowed easily between travellers, and we shared our favourite finds from exploring the islands so far. For some, the chance to disconnect and lay out on a hammock was the ideal, while others talked of searching for the perfect Guna souvenir: a handwoven mola cloth like the ones worn by the indigenous women, each uniquely decorated with bright colours and elaborate patterns.

Full and warmed by the sun peering through the palm trees, I set off to find my own adventure. A fellow traveller at lunch had told me of a small shipwreck just off the coast of the island. It was low tide, and the bow of the ship could be seen poking out of the top of the shallow water. I swam over; the wreck had been overtaken by the ocean, covered in algae and coral and surrounded by fish.

Though the underwater life surrounding the shipwreck was plentiful, the Guna have been known to practice coral mining around their islands, a practice that is widely denounced for being damaging to reefs. But for the Guna, the mining has provided them with natural material like limestone to build out the islands, allowing them to both expand their homeland and their population.

However, over time, the stripping away of the reefs has left the Guna in a particularly vulnerable place. According to the Smithsonian Tropical Research Institute, the increase in sea level around San Blas has accelerated in recent decades. This, coupled with their poor resource management, has led to significant coastal erosion. The future of San Blas is in significant danger, with the entire archipelago at risk of being underwater within a matter of decades.

Ultimately, the Guna will have to leave the islands; it’s not a matter of “if”, but “when”.

Non-profit Displacement Solutions, which assists climate-displaced peoples, estimates that approximately 28,000 people will need to be relocated from the islands onto the Panamanian mainland. Researchers have suggested this process should begin as soon as possible, as the Guna people face significant danger if extreme weather was to hit the region. But while the Panamanian government has agreed to work with the Guna on this daunting process, the Guna people have expressed apprehension about the move. Only one island community, Gardi Sugdub, has pursued government assistance to relocate, but the process has been sluggish, with plans dating back to 2010 for housing and financial assistance still not translated into actions today.

It’s also largely unknown is what exactly the move will mean for the Guna’s governmental autonomy and for their economy, as the Guna currently depend on tourism and fishing to make ends meet. There is even discussion about whether the tribe should be allowed to continue accessing the islands once the relocation is complete, since prolonged human impact would likely keep hurting the islands’ chances of survival.

Lying on the beach after my swim, it was tough to pair the vibrancy I saw around me with the dark future that’s likely in store for the archipelago. I watched locals shimmying up palm trees to pick coconuts. A short distance away, a mother and daughter were hanging up a mola-decorated blouse on a clothesline outside their home. Heading down to the shore, I joined a group of fishermen inspecting the day’s catch, which included the largest fish I’d ever seen, held up by the proud fisherman, his finger hooked through the fish’s eye.

Soon, Eulog’io came over and tapped me on the shoulder, leading me back over to the boat. It was time to head back to the mainland. But as we set off and the islands slowly disappeared behind us, he suddenly cut the engine.

“Jump out,” he said.

Exchanging uncertain glances, my fellow passengers and I peered over the edge of the small boat. The clear, shallow water did little to hide the countless starfish dotting the sand below, and we all slipped into the warm water to get a closer look at the magnificent sight.

It was seeing the Guna’s knowledge of spots like that – in the middle of the sea, with no visible markers around – that showed just how knowledgeable of and in-sync the Guna are with San Blas. It’s the land they bitterly fought for, turned into a home, learned every corner of, and soon, will have to leave behind.

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